Space heater and heating system



Dec. 18, 1962 c. R. FREEMAN SPACE HEATER AND HEATING SYSTEM 2Sheets-Sheet 1 Filed Aug. 17, 1959 NT ME I r; 4 I

Dec. 18, 1962 c. RKFREEMAN SPACE HEATER AND HEATING SYSTEM 2Sheets-Sheet 2 Filed Aug. 17, 1959 m 82. 3 ud United States Patent3,068,854 SPACE HEATER AND HEATING SYSTEM Carl R. Freeman, 1237 W. 47thSt., Chicago, Ill. Filed Aug. 17, 1959, Ser. No. 834,261 2 Claims. (Cl.126110) This invention relates to heating systems and, moreparticularly, to heating systems of the forced hot air type for spaceheating of buildings.

It is one of the objects of the present invention to provide a spaceheating system that is applicable for heating a large number of roomswherein there are variations in the relative heating requirements of therespective rooms. For instance, in the heating of rooms of a schoolbuilding or the like, two different rooms may require approximately thesame amount of heat at one time and under one set of conditions andrequire relatively different amounts of heat under different times andunder difierent conditions. In accordance with the principles of thepresent invention, each room (or groups of rooms) is provided with oneor more air supply ducts in the conventional manner. Each duct, however,receives its air from two sources, one of which supplies hot air and theother supplies cooler air. By mixing the two air supplies in varyingamounts, as determined by the needs of each room, the supply of heat toeach room may be regulated while maintaining a substantially constantair flow into the room as may be needed, for instance, for ventilation.

In accordance with the principles of the preferred embodiment of thepersent invention, air, which may be return air from the rooms, outsidefresh air, or a mixture of the two, is blown by a single blower alongtwo separate paths. The air in one path passes through the heatexchanger, and the air in the other path substantially bypasses the heatexchanger. The air from each of the two paths is then merged under thecontrol of a thermostatically controlled proportioning damper.

It is a further object of the present invention to carry the cooler airthrough a duct or conduit that surrounds the hot air duct of the heatexchanger and is in turn surrounded by heat insulation, particularly inthe case where the heat unit or heat exchanger of the heat unit isitself in a. location that is to all intents and purposeson the outsideof the building. This rendersthe system particularly applicable-to asupplemental heat unit that is frequently necessitated when an existingbuilding is enlarged beyond the capacity of the heating system alreadyinstalled. In the case of school buildings which of late have beenenlarged this arrangement obviates the need of expensive replacementheating systems which might otherwise be necessary because of theincreased heating demand.

The attainment of the above and further objects of the present inventionwill be apparent from the following specification taken in conjunctionwith the accompanying drawing forming a part thereof.

In the drawings:

FIG. 1 is a side elevational view partially broken away and in sectionof a heating apparatus constructed in accordance with and embodying thepresent invention;

FIG. 2 is a sectional view' taken along line -2-2 of FIG. 1;

FIGS. 3 and 4 are fragmentary sectional views taken.

along lines 3-3 and 4-4 respectively, of FIG. 2; and

FIG. 5 is a fragmentary sectional view on an enlarged scale and takenalong line 5-5 of FIG. 2.

Like reference numerals designate like parts throughrectangular crosssection and including marginally interconnected walls 2, 3, 4, Sand anend wall 6. Preferably, each of the walls 2, 3, 4, 5, 6 are formed ofinner and outer sheet metal members 7, 8 having suitable heat insulatingmaterial 9 confined therebetween. Mounted on the outside of the end wall6 is a conventional oil or gas burner 10 which is provided with a tube11 projecting through the end wall 6 a short distance into the casing 1.Within the casing 1 the tube 11 communicates with a combustion chamber12, the latter, in turn, communicating through a short tube 13 with arelatively long heat exchanger 14.

The heat exchanger 14 includes a cylindrical wall 15 extendinglengthwise of the housing 1 and spaced from the walls 2, 3, 4, 5thereof. Adjacent to the combustion chamber 12, the heat exchanger 14includes an end wall 14' and at its other end the heat exchanger 14includes a closure plate 16. Rigidly attached at one end to thecylindrical wall 15 and extending radially outwardly therefrom aresupporting fins 17 which are also each rigidly secured at their outerends to the inside faces of the walls 2, 3, 4, 5 so as to hold thecombustion chamber 12 and heat exchanger 14 substantially coaxial withthe longitudinal axis of the casing 1. Adjacent to the closure plate 16the cylindrical wall 15 is provided with a radially outwardly extendingpipe 18 which projects through the wall 5 and communicates with theintake side of an induced draft fan 19. The discharge side of the fan 19is connected to a duct 20 which preferably runs along the side of thecasing 1 exteriorly thereof and is in turn connected to a vertical fluepipe 21. Consequently, when the fan 19 is in operation, hot gaseousproducts of combustion formed in the combustion chamber 12 will be drawnaxially along the interior of the heat exchanger 14 in a directiontowards the closure plate 16 and then radially outwardly thereof throughthe pipe 18 for delivery to the duct 20 and'flue pipe 21.

Mounted within the cylindrical wall 15 and extending axially along theheat exchanger 14 is a plurality of circumferentially spaced air tubes22 which extend from one end of the heat exchanger to the other andare-open at the opposite ends thereoh The air tubes 22 are supported attheir opposite ends in-the end plate 16 and end wall 14', respectively.Circular or disc baflle plates 23 are suspended from the tubes 22 inspaced parallel relationship and between them there is provided anannular plate 24 surrounding the tubes 22 all for forcing the hotgaseous products of combustion to flow in a tortuous path around thetubes. Furthermore, the tubes 22 are spaced radially inwardly of thecylindrical wall 15 so that the gaseous products of combustion can flowcompletely around the air tubes 22 substantially throughout the entirelengths thereof.

Enclosing the heat exchanger 14 and combustion chamber 12 is acylindrical wall member 25 which is coaxial with the heat exchanger 14and the combustion chamber 12 and lies in inwardly spaced relationshipto the casing 1 so as to form with the casing 1 a conduit 26 whichsurrounds the heat exchanger 14 and combustion chamber 12. Preferably,one end 27 of the wall member 25 terminates in approximate alignmentwith the end plate 16, and the wall member 25 is held in spacedrelationship with the cylindrical wall 15 by means of fins 28, thelatter being mounted on the outside of the cylindrical wall 15 andextending radially outwardly therefrom for rigid connection with thewall member 25.

Adjacent to the end wall 6 the member 25 and walls 3, 5 are bent in theprovision of lateral extensions 29', 30 to form with the end wall 6 apair of discharge ducts 31, 32 on each side of the structure. Rotatablymounted in the extensions 29, 30 and end wall 6 is a plurality of spacedparallel shafts 33 upon each of which is mounted a pair of dampers 34,35 at right angles to one another. The dampers 34, 35 are locatedrespectively in the discharge ducts 31, 32. Each shaft 33- isindividually driven as by a suitable thermostatically controlledelectric motor 36 which transmits power to the shaft 33 associatedtherewith, through its reduction gearing 37. The motors 36 and gearing37 may be mounted on any suitable support 37'. Connected to theextension 30 and end wall 6 is a plurality of delivery ducts 38, onebeing associated with each pair of dampers 34, 35. Each delivery duct isadapted to transmit air to a desired room (or group of rooms) to beheated, as shown in FIG. wherein the several rooms are designated asRoom A, Room B, etc. The thermostat t (FIG. 2) associated with theparticular motor 36 will also be located in the corresponding room sothat operation of one set of dampers will control the flow of air to oneroom, or to a group of rooms if the space to be supplied by one of theducts 38 constitutes more than one room. In connection with the presentinvention, it should be understood that the delivery ducts 38 can be'mounted in the building being heated in any conventional manner and,therefore, this arrangement is not shown in detail in the presentapplication. Furthermore, the wiring diagrams for the thermostats,meters 36, and the like are not shown herein since motor-driven,thermostatically controlled dampers are known in the art.'

Mounted within the housing 1 in forwardly spaced relation to the closureplate 16 is a fan 39 which draws air from two ducts 4G, 41 throughsuitable air filters 42. The ducts 40, 41 are, respectively, forpurposes of providing fresh air into the heating system and for drawingreturn or cold air from all of the rooms being heated.

In operation, the fan 39 draws air from the fresh-air intake andreturn-air ducts 40, 41, respectively, and forces it through the heatexchanger 14, that is, through the tubes 22 and throughthe'space betweenthe combustion chamber and the cylindrical member 25, and also theconduit 26 that surrounds the member 25, as illustrated by he arrow h nc i F G- 2- h t r P h in i te by the arrows h is such that the airdelivered from the fan 39 will flow on the outside of the cylindricalwall and also through the air tubes 22 whereupon this air will heheated. The air will then flow outwardly through the heat exchanger andwill be delivered to the discharge duct 31 which is in communicationwith the discharge side of the heat exchanger 14. The air flowingthrough the conduit 26, as indicated by the arrows 0, will by-pass theheat exchanger and will, therefore, be relatively cool as compared tothe; air flowing through the heat exchanger. The

' jcooler air will thus ilow through the conduit '26 and into thedischarge duct 32 which communicates therewith. The heated and unheatedair will then :pass across the dampers 34, 35 and will be blended as thetwo supplies of air enter each delivery duct 38. The proportions of hotand cool air entering each delivery duct 38 and delivered to the roomassociated therewith will depend upon the adjustment of the particulardamper shaft 33. Thus,

' -when the dampers 34, 35 are in the position shown in a FIG. 2 and infull lines in FIG. 5, the cooler air supply.

will .be cut off and all of the hot air will be delivered to theassociated delivery duct 38. However, when the dampers 34, 35 arerotated 90 to the position shown in dotted lines in FIG. 5, the hot airsupply will be cut olf 7 and only the cooler air will pass into thedelivery duct 38. When the dampers 34, 35are in any intermediateposition, the hot and cold air will both enter the delivery duct 38, andthe proportions of each will depend upon the amohnt each of the dampersis open. Sincethe motors 3,6 are ordinarily thermostatically controlled,it will be apparent that when a particular room temperature drops, themotor 36 will be rotated so as to open the damper 34 a greater amountand correspondingly close the damper 35. Similarly, if the roomtemperature should exceed the selected amount, the motor will rotate andcause the damper 34-toicl0lse and damper 35Vto open, thereby in- 4creasing the amount of cold air passing into the delivery duct 38.Consequently, it is possible to mix the hotter and the-cooler air inselected proportions while at the same time maintaining a relativelyconstant flow of air into and out of each room irrespective of theposition of the dampers.

The present invention may be used as the sole source of heating abuilding having a plurality of rooms. Furthermore, the heating apparatusof the present invention may also be used as a supplemental heating unitin an existing building to enlarge the heating capacity thereof.

In connection with the present invention it should be noted that thecooler air in the conduit 26 forms an insulating means surrounding theheat exchanger 14 which supplements the insulation in the walls of thehousing 1. This is. of particular advantage when the apparatus ismounted on the outside of a building as, for example, on the roofthereof, in which case the outside of the housing is exposed to ambientair temperatures considerably lower than the temperature of the airwithin the system. Furthermore, when the dampers are adjusted so thatair is flowing through the conduit '26 and into one or more of thedelivery ducts 38, theinsulating elfectiveness of the flowing air in theconduit 26 is actually increased in proportion to the rate of air flowthrough the conduit 26; Consequently, some of the heat loss transferredfrom the heat exchanger to the conduit 26 will be absorbed by the airflowing in the conduit 26,'thereby reducing the total heat ultimatelylost through the insulated casing. i

In compliance with the requirements of the patent statutes I have hereinshown and described a preferred embodiment of the invention. It is,however, to be understood that the invention is not limited to theprecise construction herein shown, the same beinjg merely illustrativeof the principles of the invention. What is considered new and desiredto be secured by Letters Patent is:

1. Heating apparatus comprising a housing havingan insulated housingwall for reducing the heat loss from the inside of the housing to theoutside thereof, a heat exhang mo nte w th n and su rsund d by the houel sai h exchang r incl d ng a .combu tiq chamhe and a a m mber adja entt an in comm tion w h s d combustion hamb a d rm n tubu a means. or hPas of h ated pr cts f omb st on i on d r ct oii x a y t e thm'u s dheat xchan er als nc ud n a pl li y 9 axia ly weed ng t es in said, i am be an t ou which passes ir b heated, th

he l m e of t heat ex h r and he usin a wall and in spaced relation toeach, the second wall member and housing wall forming a conduit formarrow rof air therethrough by-passing the heat exchanger,

circulating means for delivering a flow of air siniultarie ously throughthe tubes, the space between the two wall members, and the conduit in adirection substantially opposite to the flow of heated products ofcombustion through the ubu r eans, the air in s id cvn u t f min a heatinsulat ng layer between the tubular means and the insulated wa l sothat the heat losses from the heat exchanger to the outside 'ofthe'housing are reduced-by supplying a'quantity of heat to the airflowing in said eon-.,

duit, a-pair of dischargeducts in communication, respectively, with thedischarge ends 9f. the conduit heat exchanger. a d r du t in communicaia t h the outlet sides of the discharge ducts, a damper in each of saiddischarge ducts, said. dampers being rotatable about 'a common axis andlying in planes intersecting each other, a and means for rotating thedampers together to blend the from the discharge ducts in selectedproportions,

one of said dampers being fully closed when the other 2. Heatingapparatus comprising a housing having an insulated housing wall forreducing the heat loss from the inside of th housing to the outsidethereof, a heat exchanger mounted Within and surrounded by the housingwall, said heat exchanger including a combustion chamber and a wallmember adjacent to and in communication with said combustion chamber andforming tubular means for the passage of heated products of combustionin one direction axially therethrough, said heat exchanger alsoincluding a plurality of axially extending open-ended tubes in saidmember and through which passes air to be heated, the tubes being spacedinwardly of the wall member and having axially spaced baffle platesadjacent thereto so that the heated products of combustion can flowsubstantially completely around the tubes in a tortuous path, a secondWall member enveloping the wall member of the heat exchanger, saidsecond wall member lying between the wall member of the heat exchangerand the housing wall and in spaced relation to each, the second wallmember and housing forming a conduit for the flow of air therethroughby-pa-ssing the heat exchanger, air circulating means for delivering aflow of air simultaneously through the tubes, the space between the twowall members, and the conduit in a direction substantially opposite tothe flow of heated products of combustion through the tubular means, the

air in said conduit forming a heat insulating layer between the tubularmeans and the insulated wall so that the heat losses from the heatexchanger to the outside of the housing are reduced by supplying aquantity of heat to the air flowing in said conduit, a pair of dischargeducts in communication, respectively, with the discharge ends of theconduit and heat exchanger, a delivery duct in communication with theoutlet sides of the discharge ducts, a damper in each of said dischargeducts, and means for operating the dampers together to blend the airfrom the discharge ducts in selected proportions.

References Cited in the file of this patent UNITED STATES PATENTS1,015,204 Murray Jan. 16, 1912 1,389,408 Wilputte Aug. 30, 19211,416,255 Boone May 16, 1922 1,936,003 White Nov. 21, 1933 2,015,960Norris Oct. 1, 1935 2,056,465 Juhnke Oct. 6 1936 2,440,052 Lingen et alApr. 20, 194-8 2,593,759 Horn Apr. 22, 1952 2,600,020 Pietsch June 10,1952 2,804,869 Besser Sept. 3, 1957 2,897,804 Andersen Aug. 4, 1959

